Longest-ever sub-ice core reveals millions of years of climate history

An international research team, including faculty from Binghamton University, SUNY, has drilled the longest-ever sediment core from beneath an ice sheet, providing a record stretching back millions of years that could help climate scientists predict the future of the West Antarctic Ice Sheet in a warming world.

“To our knowledge, the longest sediment cores previously drilled under an ice sheet are less than 10 m,” said Molly Patterson, co-chief scientist and associate professor of earth sciences at Binghamton University. “We exceeded our target of 200 m, and undertook this 700 km from the nearest base—this is Antarctic frontier science.”

The 228 m core, extracted from beneath 523 m of ice at Crary Ice Rise on the edge of the West Antarctic Ice Sheet, preserves an archive of past environmental conditions, including periods when Earth’s temperatures were significantly warmer than today. “This record will give us critical insights about how the West Antarctic Ice Sheet and Ross Ice Shelf is likely to respond to temperatures above 2°C. Initial indications are that the layers of sediment in the core span the past 23 million years, including time periods when Earth's global average temperatures were significantly higher than 2°C above pre-industrial,” said co-chief scientist Huw Horgan.

Analysis of the sediment revealed evidence of both ice-sheet deposits and open-ocean conditions, indicated by shell fragments and remains of light-dependent marine organisms. “This new record provides sequences of environmental conditions through time, and ground truths the presence of open ocean in this region…analysis will help us quantify the environmental factors that drove the ice sheet retreat, such as determining what the ocean temperatures were at that time,” Patterson added.

The operation faced significant logistical and technical challenges. The team used a hot-water drill to melt through 523 m of ice and then lowered more than 1,300 m of drill pipe to extract the core. Field operations were conducted in a remote tent camp nearly 1,100 km from the nearest main base, supported by Antarctica New Zealand and the U.S. Antarctic Program.

“Our multi-disciplinary international team is already collaborating to unravel the climate secrets hidden in the core. With our drilling system having been put to the test under these tough Antarctic conditions and passing with flying colours, we're looking ahead to plan future drilling to continue our mission to learn more about the sensitivity of the West Antarctic Ice Sheet to global warming,” Horgan said.

The core has been transported to Scott Base and will be distributed to SWAIS2C scientists worldwide for further analysis, offering a unique window into the past behaviour of one of the world’s most critical ice sheets.

By Vugar Khalilov